Open hole tool joint protector



May 11, 1943. DE MONT G. MILLER OPEN HOLE TOOL JOINT PROTECTOR Filed Feb. :5, 1941 M 8 M??? Z 49 48 4Q W ky Q Patented May 11, 1943 OPEN HOLE TOOL JOINT PROTECTOR De Mont G. Miller, San

to Patterson-Ballagh C Call, a corporation Application February 3, 1941, Serial No. 377,115

, 3 Claims.

The present invention relates to a protector or stabilizer of the type employed on drill pipe to prevent wear during drilling operations. In the drilling of oil wells, contact may occur between the tool joints of the revolving drill pipe and either the walls of the well or the well casing, depending upon whether the drill pipe is revolvlng in an open hole or within a Well casing. When the drill pipe is rotating within a well casing, excessive wear of the well casing will be occasioned by contact between it and the tool joints of the drill pipe unless means are provided to prevent such contact. When the drill pipe is revolved in an open l.ole, with certain formations at least, the tool joints of the drill pipe undergo excessive wear.

At present there are employed certain so-called protectors or stabilizers of rubber around the drill pipe for the purpose of acting as bumpers to eliminate contact between the tool joints and either the walls of the well or the well casing. When the rubber protectors or stabilizers are employed on that portion of the drill pipe rotating within a well casing, they operate satisfactorily with little wear. Attempts to equip that portion of the drill pipe which is revolving in an open hole with a stabilizer frequently are unsatisfactory. The contact between the rubber stabilizer and the walls of the open hole frequently results in a rapid destruction of the rubber stabilizer.

It is the general object of the present invention to provide a novel form of protector or stabilizer for drill pipe for the purpose of protecting tool joints of drill pipe while the same are rotating in an open well hole.

I have discovered that the destruction of rubber stabilizers or protectors which occurs in an open hole may be avoided in the following way: After the rubber stabilizer or protector has been expanded and placed upon the drill pipe, I slip over the stabilizer or protector a short section of steel shell or casing and fasten or look the'same around the stabilizer or protector by suitable rings. In such a way the rubber stabilizer or protector is provided with what might be considered a short section of well casing individual to or housing only the stabilizer or protector. The stabilizer or protector still retains its properties as a bumper for eliminating destruction of the tool joints of the pipe. When the steel shell or short section of casing surrounding the stabilizer or protector strikes the side walls of the open hole, the steel shell ceases to rotate and the rubber protector within the steel shell then proceeds to Marino, Calif., assignoi' orporation, Los Angeles,

California turn relative to the shell, acting as a sort of rubber bearing.

While it may be possible to satisfactorily enclose any usual form of rubber stabilizer or protector with the steel shell of the present invention for the purpose of operation in an open hole, I prefer to employ a specially constructed rubber protector or stabilizer. Such specially constructed rubber stabilizer or protector differs from those ordinarily employed in several respects. The rubber protector or stabilizer employed'with the present invention is of an outside diameter somewhat smaller than the outside diameters of rubber protectors normally employed, and is provided at its ends with suitable retaining lips designed for receiving the retaining rings associated "with the steel sleeve. The lips of the rubber protector or stabilizer are designed to prevent any metal to metal contact between the drill pipe and the steel shell or its retaining rings. I find it preferable to provide a close or packing fit between the retaining rings and the rubber stabilizer or the lips thereof in order to prevent or inhibit the passage of mud fluid into the space between the steel shell and rubber stabilizer. On the other hand, to reduce friction and wear between the rubber stabilizer and steel shell, I find it desirable to employ a steel shell the inner diameter of which is slightly larger than the exterior diameter of the rubber stabilizer.

The protector of the present invention, together with various further objects and advantages of the invention, will be best understood from the following description of a preferred form or example of a protector embodying the present invention. For this purpose I have hereafter described the preferred form of the invention in connection with the accompanying drawing, in

which- Figure 1 is a vertical section through a well hole, showing the apparatus of the present invention in use;

Figure 2 is an enlarged vertical section of the protector, showing the same in place on a section of drill pipe; and

Figure 3 is a view of one of the split rings.

Referring to the drawing, I have indicated the apparatus in operation in a well hole A, which may be of such shape as to cause the drill pipe to be brought into contact with the sides of the well hole, as indicated. In the drawing, 2 indicates a section of drill pipe such as may be employed in the art of drillingwells by the rotary method, and the drill pipe 2 is indicated as provided with any usual or preferred form of tool I use the term joint 2, the wear of which against the sides of the well hole is to be eliminated through the use of the protector of the present invention.

The protector of the present invention includes a rubber protecting sleeve or stabilizer 3 which, in accordance with the usual technique in the art, is originally formed with an inner diameter considerably smaller than the exterior diameter of the drill pipe 2, and which is expanded or stretched by suitable appliances in order to be passed over the drill pipe and tool joints thereof into a suitable operating position, where the elasticity of the member will aflford a considerable pressure, acting to grip the rubber sleeve 3 firmly on the drill pipe 2.

While I have herein referred to a rubber sleeve, rubber in a generic sense in order to include all rubber-like materials and substitutes therefor. While because of its lower cost natural rubber, after suitable treatment, may be generally employed as the material of the rubber sleeve 3, there are certain advantages for the protector of the present invention in making the rubber sleeve 3 of some of the rubber substitutes derived from coal or petroleum products, since certain of such rubber substitutes are more resistant to the .action of oil than natural rubber products.

The rubberlike sleeve 3 is indicated as provided at its ends with lips l of a reduced outer diameter, which serve the purpose, as hereafter pointed out, of providing a mounting for the retaining or looking rings of the protector and as a means to prevent any possible contact between the drill pipe and the steel shell or metallic retaining rings thereof.

After the installation of the rubber sleeve 3 upon the drill pipe, I slip over the exterior of such sleeve 3 a short steel shell 5, which steel shell 5 preferably has an inner diameter slightly larger than the outer diameter of the rubber-like sleeve member 3 in order to create a slight clearance, as indicated at 6, between such members. I then lock to one end of the steel shell 5 a split ring I. Preferably this is accomplished by welding the split ring 1 to the end of the steel shell 5, and for this purpose it is preferable to slide the steel shell partly back off the rubber sleeve 3 during the welding step. After cooling oil the weld, the steel shell is slipped back over the rubber sleeve 3 and a similar split ring 8 welded to the opposite end. The split rings 1 and 8 are each formed with an inner diameter sufficiently small to have a packing fit against the lips 4 of the rubber sleeve 3, in order to inhibit the flow of mud fluid back of the steel shell 5. In inserting the split ring 8, it is preferably pushed against the ends of the body of the rubber sleeve 3 in order to form additional packing area. In

the construction of the protector of the present invention, the rubber sleeve 3 has an outside diameter somewhat smaller than the rubber sleeves ordinarily used. The outside diameter of the rubber sleeve 3 may correspond to or be slightly greater or less than the outside diameter of the tool joints 2 of the drill pipe, thus not bein ellective without the aid of the steel shell for preventing contact of the tool joints and the walls of the well hole. The steel shell 5 has an outer diameter suiliciently greater than the outside diameter of the tool joints 2* of the drill pipe in order to be effective in protecting the tool joints from wearing contact. The inner diameters of the split rings 1 and 3 should be slightly smaller than the exterior diameters of the tool joints 2' in order that after the protector has been installed in its proper position upon the drill pipe 2, it cannot be forced over the tool joints by accidents in drilling operations.

While the particular form of the protector herein described is well adapted to carrying out the objects of the present invention, it is to be understood that various modifications may be made, and the invention is of the scope set forth in the appended claims.

I claim:

1. A device for protecting drill pipe in open hole, which comprises an elastic protector member stretched over the pipe to be protected and resiliently gripping said pipe, a short metallic sleeve fitted over the elastic protector member but provided with clearance with said protector sleeve and rotatable relative to said sleeve, and ring members having a packing fit with said protector sleeve and maintained spaced from said pipe by said protector sleeve, said ring members being secured to said metallic sleeve for retaining the same in position.

2.A device for protecting drill pipe while rotating in open hole, which device includes an elastic protector member stretched over the drill pipe and elastically gripping the pipe, a metallic shell enclosing said elastic member and having a slight clearance therewith and in which said elastic member is adapted to rotate, and retaining rings connected to said metallic sleeve and having a packing fit with said elastic member, said retaining rings being spaced from the pipe by said elastic member.

3. A device for protecting drill pipe while rotating in openhole, which device includes an elastic protector member stretched over the pipe to be protected and elastically gripping the pipe, said elastic protector member having lips of reduced outer diameter at its ends providing shoulders and bearing surfaces, retaining rings having a packing fit with said lips and spaced thereby from said pipe and engaging said shoulders, and a metallic shell extending from retaining ring to retaining ring, enclosing said elastic member, and having a slight clearance therewith whereby in normal operation said metallic shell is adapted to rotate relative to said elastic member.

DE MONT G. MILLER. 

